But Mr Balls said the government was not investing enough in affordable homes and had presided over the "lowest level of house-building since the 1920s".

"If you boost demand with Help to Buy and don't do enough on supply, the price goes up, it's harder to get into the housing market, the economy becomes more unbalanced and the cost of living crisis gets deeper," he told BBC Radio 5 Live's Pienaar's Politics.

Bank levy

Earlier, on the Andrew Marr Show, he had said the chancellor was "only ever tough when he is having a go at the weak and the voiceless".

By contrast, he argued, Labour would "take away the winter allowance from the richest pensioners", "re-introduce the 50p tax rate on incomes over £150,000" and impose a "mansion tax" on properties worth more than £2m.

A future Labour government would also use a bank levy "to pay for more childcare for working parents", bring back the 10p income tax rate, and abolish the "unfair and perverse marriage tax break, which George Osborne has given only to a third of married couples".

"These things are all paid for. I am not making any spending commitments which we can't say how we'll pay for them," he said.

The shadow chancellor also defended the previous Labour government's record in office on public spending.

"There was a global financial crisis," he said.

"At that point, we had the lowest level of national debt of any big country and George Osborne, the Conservative shadow chancellor, had matched Labour's level of public spending.

"Am I going to apologise for the level of public spending that George Osborne, Alistair Darling and Gordon Brown agreed on in 2007? Absolutely not.

"What we did on the NHS was hugely important, the national minimum wage, not joining the euro.

"The economics of this is that we had a very low deficit [and] low national debt before the crisis. What happened was a collapse in tax revenues because of the crisis.

Writing in the Mail on Sunday, he said: "I made it clear at our spring conference last week that further rises would be a top priority for our party in any negotiations that might be required should the British people deliver a hung parliament.

"We aspire to raise it substantially to £12,500."

He also said the Lib Dems were committed to sticking to the plan to eradicate the deficit and get the nation's finances on a firm footing by 2018-19.

"That means that there is a period of further deficit reduction required after the next General Election."